Modular electronic assemblies containing interconnected semiconductor (SC) die and other electronic components are much used. It is important that such assemblies be small in size, yet have good electrical and thermal properties and be able to incorporate various types of semiconductor die and other electronic components. Such assemblies are used when it is not practical or possible to incorporate all of the desired circuitry in a single semiconductor integrated circuit (IC). In such assemblies, several different types of IC's and other semiconductor devices may need to be housed and interconnected in the desired configuration. In order to save space and improve the overall properties of the assembly it is useful to mount unpackaged semiconductor die within the assembly and then interconnect them to provide the desired overall electrical function. The overall cost of such assemblies is a sensitive function of the manufacturing methods used in their fabrication and the batch size, that is, the number of such assemblies that can be fabricated simultaneously. The small size and fragility of unpackaged semiconductor die and other unpackaged components adds to the difficulty of manufacturing assemblies using unpackaged die, especially where the dimensions of the assemblies (e.g., area and thickness) must be minimized. For example, in consumer electronic products such as cellular telephones and personal digital assistants (PDAs), the electronic assemblies providing the desired functionality must be as thin and as small as possible so that the outer dimensions of the device, especially the thickness may be minimized. Further, while such assemblies can often be readily fabricated on a laboratory scale, scaling up the manufacturing process for high volume and low cost can present significant challenges. Accordingly, there is an ongoing need for volume manufacturing methods capable of efficiently providing compact electronic assemblies with good thermal properties and low connection impedance for attachment to the circuit motherboard or tape of the finished product.
Accordingly, it is desirable to provide an improved method of manufacture of electronic assemblies that permits use of multiple interconnect layers and multiple electronic components when needed, and at the same time, that is adapted for volume manufacture. It is further desirable that the manufacturing methods and materials employed be compatible with present day manufacturing capabilities and materials, and not require substantial modifications of available manufacturing procedures or significant increase in occupied area or other increase in manufacturing costs. It is further desirable that the overall thickness and lateral area of the assembly be minimized. Other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawing and the foregoing technical field and background.